Showcases of this type must therefore satisfy various kinds of requirements, in relation to the storage and integrity of the objects displayed. Moreover, of course, these showcases must ensure maximum visibility of the objects displayed.
In order to improve visibility, manufacturers of showcases try as much as they can to use transparent materials—typically glass—for the walls of the showcase. As well as ensuring maximum visibility of the objects displayed, the extensive use of glass is often desired by designers of showcases because the transparency of the material allows the objects displayed to be given maximum visual impact.
Therefore, showcases have been developed having a base block with a case formed by panels on top; the base block houses all of the technical components necessary to ensure that the environment inside the case is protected and is thus normally closed by non-transparent walls, which hide all of the technical components from view; vice-versa, the walls of the case are made entirely or partially from glass, for the aforementioned reasons.
The possibility of access to the inside of the case, for the housing, removal or maintenance of the objects displayed, is normally obtained by providing for at least one of the side panels to be openable. For this purpose, opening supports of various kinds are used, which allow opening by rotation or roto-translation of the panel (more or less complex hinges) or by sliding (sliding guides). These opening supports must clearly ensure the correct closure of the openable panel, but must also allow an opening that is as wide as possible, so as to make access possible and easy also to arrange very large-sized objects (relative to the size of the showcase), possibly also in cases in which the weight of the object forces the uses of a fork lift or similar to move the object.
Therefore, there is a problem of maximising the degree of opening of the openable panel, even in the presence of panels made of transparent material.
Consequently, the present invention concerns a showcase as defined herein.
In particular, the invention concerns a showcase for preservation and display of objects, comprising a fixed casing and at least one openable panel made of glass mounted on the fixed casing through opening supports, characterised in that the opening supports comprise:                a pair of upper rods and a pair of lower rods, all having a same length, pivoted to the fixed casing at respective first upper and lower rod pins;        an intermediate structure, pivoted to the upper and lower rods at respective second upper and lower rod pins;wherein the rod pins have a pivoting axis parallel to a main direction;wherein the distance on the fixed casing between the first upper rod pins and the distance on the intermediate structure between the second upper rod pins are equal to each other, as well as the distance on the fixed casing between the first lower rod pins and the distance on the intermediate structure between the second lower rod pins are equal to each other, so that the four rods form an articulated parallelogram system for the movement of the intermediate structure with respect to the fixed casing;        and a hinging system along the main direction, between the openable panel and the intermediate structure, so as to allow the openable panel to rotate with respect to the intermediate structure.        
With this structure, the opening of the openable panel is divided substantially into two steps.
In a first step, the parallelogram system formed by the rods determines a roto-translational movement of the intermediate structure and with it of the openable panel with respect to the case, so that the openable panel passes from the closed position, in which the openable panel completely closes an opening space of the fixed casing, to a partially open position, in which the openable panel leaves a part of the opening space of the fixed casing partially free. In this first step of opening, the hinging system between intermediate structure and openable panel is left inactive (and possibly blocked), so that the openable panel and the intermediate structure move jointly.
In a second step, it is the parallelogram system that is left inactive (and possibly blocked), so that the intermediate structure remains fixed to the fixed casing, whereas the hinging system is used to allow the openable panel to rotate with respect to the intermediate structure, until it reaches a completely open position. In this position, the openable panel can be positioned on the side of the fixed casing and the opening space is thus made completely free, so as to allow easy access to objects of any size.
Closing clearly proceeds in reverse, also in two steps.
Preferably, the intermediate structure comprises at least an upper bar and a lower bar, respectively pivoted to the upper and lower rods at the second upper and lower rod pins. Preferably, the openable panel comprises at least an upper bar and a lower bar, respectively pivoted to the upper bar and to the lower bar of the intermediate structure through the hinging system. Preferably, the hinging system comprises an upper hinge between the upper bars of the intermediate structure and of the panel and a lower hinge between the lower bars of the intermediate structure and of the panel. These solutions all help to obtain the maximum structural simplicity, whilst ensuring the aforementioned possibilities of actuation.
In a preferred embodiment, the upper hinge and the lower hinge are two roto-translational complex hinges. Here and hereafter the expression “roto-translational complex hinges” means to indicate a hinging mechanism that is not limited to ensuring a simple possibility of rotation between the parts, but rather ensures that the rotation between the parts is also associated with a translation. Complex hinges of this kind are per se known and are obtained with systems of rods and pins, variously configured according to the roto-translational movement that is wished to be obtained.
Preferably, each of the two roto-translational complex hinges comprises a first fork fixed to one of the bars, a second fork fixed to the other of the bars, and three rods pivoted between the first and the second fork, in which:                a central one of the rods is pivoted to the first fork between opposite arms thereof according to a first pivoting axis,        the central rod is pivoted to the second fork between opposite arms thereof according to a second pivoting axis,        two outer ones of the rods are pivoted to the first fork outside of the arms thereof according to a third pivoting axis,        the two outer rods are pivoted to the second fork outside of the arms thereof according to a fourth pivoting axis,in which the four pivoting axes are parallel to each other and to the main direction, and in which, moreover:        on the first fork, the first pivoting axis is located between the third pivoting axis and the ends of the arms of the first fork,        on the second fork, the fourth pivoting axis is located between the second pivoting axis and the ends of the arms of the second fork.        
Even more preferably, the two complex hinges are fixed with the respective first forks to the bars of the intermediate structure and with the respective second forks to the bars of the openable panel.
Hinges thus configured ensure that the bars of the openable panel rotate with respect to the bars of the fixed structure and at the same time move away from them, thus facilitating the passing over the edge of the case of the showcase, even when it has an acute angle.
In another preferred embodiment, the upper hinge and the lower hinge are two simple pin hinges. This solution is clearly simpler and more cost-effective and may be preferred when the passing over the edge of the case of the showcase is not problematic, for example because the corresponding angle is sufficiently large.
Preferably, the hinging system is positioned at about half of the width of the openable panel. This feature ensures that the openable panel is supported by the intermediate structure in a substantially barycentric position; with openable panels of large dimensions and of high weight, this feature thus makes it possible to more easily maintain conditions of static equilibrium of the openable panel during opening and closing.
Preferably, the rods, in closure conditions of the openable panel, are extended parallel to the openable panel, and the length of the rods between the first and the second rod pins is equal to about one quarter of the width of the openable panel.
In this way, in the first part of the opening step the openable panel moves in a direction away from the opening space of the fixed casing, and equally in the final part of the closure step the openable panel moves in a direction towards the opening space of the fixed casing. Therefore, the invention can thus be used directly also on showcases that have—between the openable panel and the fixed casing—a seal obtained through compression gaskets, i.e. without it being necessary to provide any specific different movement to obtain the compression/decompression of the gaskets.
The main direction, according to which both the hinging system and the pivoting axes are arranged, is typically vertical, since it is the position of the openable panel of most showcases; however, this does not mean that it cannot be oriented differently, for example inclined with respect to the vertical or even horizontal, according to the configuration of the showcase.
Preferably, the showcase comprises support and sliding guides mounted on the fixed casing in a position such as to provide support for the rods when the openable panel is in complete or partial closure and/or opening position. This facilitates the movement even in the presence of heavy doors and makes it more precise; in particular, this support can be very useful in the closure position (and in intermediate positions close thereto), to ensure the precision of closure of the openable panel.